• 한국해양학회지
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• v.10 no.1
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• pp.25-32
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• 1975

Continued to the previous paper, the present investigation deals with stronitium-90 activities and calcium contents among 54 samples of edible marine algae collected along the coast of Korea during September, 1973 and April, 1974. The calcium contents are variable 2.0-17.8%, and 6.38% on an average. Most of the members investigated contain 2-4% in green and red algae, and 8-10% in brown algae. Strontium-90 activities are 0.32-0.37 pCi/l in sea-water, and 0.80-28.66 pCi$\^$90/Sr/g Ca in edible seaweeds. Among the algal phyla, they are 12.49 in green, 3.34 in brown, and 9.39 pCi$\^$90/Sr/g Ca in red algae, while they are 6.25 pCi$\^$90/Sr/g Ca on an average. In a single species collected at the same season, the highest activities appear mostly from the eastern coast, and from the western and southern coasts, in turn. The green algae, Capsosiphon- Enteromorpha complex show about 3 times higher activities, 28.66 pCi$\^$90/Sr /g Ca compared with the other members showing rather higher activities, and would be an indicator plant of strontium-90 activities of the marine algae along the coast of Korea.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.124-129
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• 1998

A sensitivity study has been done to determine the composition of DUPIC fuel from the viewpoint of neutronics fuel design. The spent PWR fuel compositions were generated and fissile contents adjusted by blending fresh uranium after mixing two spent PWR fuel assemblies. The $^{239}$ Pu and $^{235}$ U enrichments of DUPIC fuel were adjusted by controlling the amount of fresh uranium feed and the ratio of slightly enriched and depleted uranium in the fled uranium. Based on the material balance calculation, it is recommended that DUPIC fuel composition be such that spent PWR fuel utilization is more than 90%.. A sensitivity study on the temperature reactivity coefficient of DUPIC fuel has shown that it is desirable to increase the $^{239}$ Pu and $^{235}$ U contents to reduce both the fuel and coolant temperature coefficients. On the other hand, refueling simulations of the DUPIC core have shown that the channel power peaking factor, which is a measure of the reactor trip margin, increases with the total fissile content. Considering these neutronic characteristics of the DUPIC fuel, il is recommended to have enrichments of 0.45 and 1.00 wt% for $^{239}$ Pu and $^{235}$ U, respectively.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.41-47
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• 2006

Moisture in a building is one of the most important variables influencing building performance, human health, and comfort of indoor environment. However, there are still lacks in the knowledge of understanding the moisture problem well and controlling moisture. Accordingly, in order to provide the fundamental data to control moisture contents in the indoor air, this study was to predict moisture contents transferred through building envelopes and indoor moisture generation rate. Moisture transfer model was made by physical relations in each node, and the indoor moisture generation rate was gained by comparing the model with experimental analyses. From the study, we found out that moisture generation rate was critical and day-periodic, so that we predicted the indoor moisture content by substituting the constant value gained from the average in a day for the moisture generation rate.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.79-87
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• 2015

A thermochemical equilibrium model was constructed for predicting composition of synthesis gas in biomass gasification. The model included estimation of equilibrium constants using Gibbs free energy. After constructing the model, the results were compared with the experimental values and predictions from a previous model. Gas compositions were reasonably well agreed with them and showed effects of operational and fuel condition. When the reaction temperature increased, the lower heating values decreased due to the decrease in CH4 concentrations. The methane concentrations were lower than those observed in experimental results. The model was used to predict the gas composition and heating values for the cases of mixed fuel of charcoal and un-dry woodchips. Although downdraft gasifiers require fuels less than 15% of moisture contents, the model results indicated that the mixed fuel with charcoal and woodchips which had over 25% of moisture contents could be used in the downdraft gasifiers. It might be explained by increase in energy density resulting from mixing charcoal. The results imply that the efforts and costs for drying biomass fuels could be reduced by mixing charcoal or fuels with higher calorific values.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.493-498
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• 2008

Particles or deposit formed by corrosion of the pipe material bring about bad influences on the heating systems with inconvenience, energy loss and so on. In order to obtain the non-corrosive environments, the circulation hot water should properly be treated in several ways to satisfy one or more conditions of the followings: suitable pH-level, low hardness, low oxygen content, low conductivity, low level of chlorides and sulphur compounds and low level of solid particles. This experimental study was carried out to develope the new guidelines on the optimal water quality and directions for water quality management in heating systems. As results, it was recommended that the heating water be maintained pH-level not less than 8, hardness contents as $CaCO_3$ no more than 50 mg/L, turbidity no more than 10 NTU and T-Fe contents 1 mg/L below.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.590-600
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• 1987

Silicone-containing polyamide-imides were prepared from bis(p-chlorocarbonylphenyl)diphenylsilane (BCCDPS), pyromellitic dianhydride(PMDA) and diamines. The thermal characteristics of the above polymers had been carefully studied using a thermogravimetric analyzer. The thermal stability of polymer was decreased with increasing contents of bis(p-carbonylphenyl)diphenylsilane units(BCDPS). The effect of diamine on thermal stability of polymer led benzidine > m-phenylenediamine> 4,4'-diaminodiphenyl ether > 4,4'-diaminodiphenyl sulfone. The activation energy of degradation of polymer obtained by Friedman method increased as the contents of BCDPS in the polymer decreased. The degradation temperature of polymers generally increased as the activation energy increased. The solubility of polymer increased as the content of BCDPS increased except polymers prepared with benzidine.

• Journal of Environmental Science International
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• v.3 no.2
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• pp.89-100
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• 1994

It is very important to assess accurately the terms which are included in the heat budget equation of soil surface because they are used in the UM and miso-scale circulation modeling as well as in the micrometeorological studies. Each terms in the heat budget equation change according to the soil moisture content. So, it is necessary to specify clearly the relations between soil moisture content and these terms. Special experiment with micrometeorological measurements was executed to study these relations at Environmental Research Center of Tsukuba University, Japan. The results are as follow: 1. The soil moisture contents of 1 cm and 4 cm depth are oscillated with one day Period in drying process and the amplitude of variation of 1 cm depth is greater than that of 4 cm. 2. Increase in soil moisture contents due to precipitation result in decrease of albedo with step function. 3. Sensible heat is in reverse proportion to the soil moisture content and latent heat is in direct proportion to it. Latent heat is more sensitive than sensible heat according to the soil moisture variation. Net long wave radiation have high correlation with soil moisture. 4. Comparing with the radiative term with the flux term in wetting process due to precipitation, the energy transfer of the aero and thermodynamic flux is greater than that of the radiative heat flux.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.274-280
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• 2008

The study of subjects were 8 persons. The study measured VO2max of each person and substituted METs at exercise intensity of both VO2max 50% and VO2max 70% in accordance with energy consumption formula to set exercise time at energy consumption of both 300kcal and 600kcal. And, the study substituted inclination and rate at exercise intensity that was measured at preliminary test. T, B, NK cell varied depending upon aerobic exercise to have no significant difference of exercise intensity at relative ratio of T, B, NK lymphocyte of all of lymphocytes and to have significant difference of Expenditures Calorie (p<.01) and interaction (p<.05) by T cell and Expenditures Calorie (p<.01) by B cell and Expenditures Calorie (p <.001) and interaction (p<.05) by NK cell.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3816-3823
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• 2021

The mechanical features evaluated theoretically using Makishima-Mackenzie's model for glasses xBaO-(50-x) PbO-50P₂O₅ where x = 0, 5, 10, 15, 20, 30, 40, and 50 mol%. Wherefore, the elastic characteristics; Young's, bulk, shear, and longitudinal modulus calculated. The obtained result showed an increase in the calculated values of elastic moduli with the replacement of the PbO by BaO contents. Moreover, the Poisson ratio, micro-hardness, and the softening temperature calculated for the investigated glasses. Besides, gamma and neutron shielding ability evaluated for the barium doped lead phosphate glasses. Monte Caro code (MCNP-5) and the Phy-X/PSD program applied to estimate the mass attenuation coefficient of the studied glasses. The decrease in the PbO ratio has a negative effect on the MAC. The highest MAC decreased from 65.896 cm²/g to 32.711 cm²/g at 0.015 MeV for BPP0 and BPP7, respectively. The calculated values of EBF and EABF showed that replacement of PbO with BaO contents in the studied BPP glasses helps to reduce the number of photons accumulated inside the studied BPP glasses.

• Clinical Nutrition Research
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• v.13 no.3
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• pp.156-164
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• 2024

The purpose of this study was to evaluate the nutritional adequacy of senior-friendly foods sold in Korea, focusing on protein and sodium. This study examined the nutritional content of 170 products with nutritional labels that were sold in online stores in Korea and categorized the products into 93 staple foods (cooked rice, porridge, and mousse) and 77 side-dish and snack foods (braized·steam·roast products, broth, sauces, and snacks). Then, the adequacy of the nutritional content of these foods, focusing on protein and sodium, was evaluated according to product type. The 93 staple products and 77 side-dish products had average serving sizes of 163.27 g and 127.92 g, prices of $3.25 and $2.72, and energy contents of 295.25 kcal and 141.95 kcal, respectively. For staple foods, the energy content was significantly greater in cooked rice, but the protein content and index of nutrition quality (INQ) were significantly greater in mousse. There were no significant differences in sodium content or contribution to adequate intake (AI) by product type, but the sodium INQ was significantly greater in the mousse and porridge. For side-dish foods and snack products, the protein content, contribution to the recommended intake, and INQ were all significantly greater for the braized·steam·roast products. Sauces and braized·steam·roast products were significantly higher in sodium content and contribution to the AI, while broth was significantly higher in sodium INQ. These findings can be used to guide proper product selection and nutritional management that considers the health characteristics of health-vulnerable and elderly people.